Conceptual and methodical problems in diagnostics of situative and socio-psychological factors' influence on the level of state anxiety in the framework of important activity (sport, stage, management, business) are discussed. New categories for stress and anxiety research are offered: interpersonal and intragroup anxiety, activity-based (work-based) anxiety, individual zones of optimal functioning. The experience of un-traditional employment of C. D. Spielberger's state-trait anxiety scale is described. Experimental data on interpersonal and intragroup anxiety and factors calling it forth are presented.